System05 - VHDL 6805 Compatible Core

System05 - VHDL 6805 Compatible Core


Category: System on Chip

Created: September 09, 2003

Updated: January 27, 2020

Language: VHDL

Other project properties

Development Status: Beta

Additional info: FPGA proven

WishBone compliant: No

WishBone version: n/a

License: GPL


6805 compatible CPU Core. Does not have any of the standard 6805 on chip peripherals at this stage other than the parallel I/O port. This was the first of the 68xx processors I attempted and have only just got around to completing it.. The Home Page for the project is Here


- 6805 compatible core
- 4 x 8 bit Parallel I/O ports
- Dual 8 bit Timer
- MiniUART compatible with 6850 ACIA.
- Runs with an E clock of 12.5MHz and system clock of 25MHz


- Prints out "Hello World" and waits for an input character
- Implemented on B5-X300 Spartan 2e board
- Needs to include a Multiply instruction to be compatible with the C8